A few years back, British writer-director Danny Boyle paused between his horror-thriller "28 Days Later" and his science-fiction thriller "Sunshine" to direct a charming, ramshackle comedy called "Millions," about a Scottish boy who unexpectedly comes into a great deal of money. Boyle's countrymen Garth Jennings and Nick Goldsmith are following close in his footsteps: After making their feature debut with 2005's awkwardly outsized adaptation of "The Hitchhiker's Guide To The Galaxy," they're scaling back with the kid-friendly "Son of Rambow," a quirk-heavy comedy that tonally reads almost exactly like "Millions," as executed by amateur actors having the time of their lives.

Set in early-'80s Britain, and packed with music by the likes of Gary Numan, Duran Duran and The Cure, "Rambow" centers on Will Proudfoot, a meek, weedy boy sheltered and smothered by his single mother's overbearing religious sect, the Puritan Brethren. Denied music, television, novels and friendship with non-Brethren children, he pours his creativity into drawing intricate little fantasy worlds on every available surface. A classmate, pugnacious bully Lee Carter, takes advantage of Will's credulous naivete, forcing him to serve as stuntman for an amateur film Lee is shooting for a young-directors' competition. Along the way, Lee unintentionally exposes Will to "Rambo: First Blood Part II." Will's fertile imagination latches onto the film's outsized wish-fulfillment fantasies, and soon, he's running around in the woods in a makeshift bandoleer and face paint, outpacing even Lee's enthusiasm for their home movie.

Like "Millions" (and other, similarly whimsical comedies about creativity, from "The Big Picture" to "The Science of Sleep"), "Son of Rambow" illustrates its protagonist's boundless imagination with little animated interludes, which serve as the film's most colorful, joyous moments. "Rambow" could use more of those surreal touches and less forced cutesiness; the film achieves an almost toxic level of adorability as Lee and Will play their mini-Coen brothers games while the rest of their school falls under the sway of French exchange student Didier Revol, whose junior ennui and high-'80s plastic fashions seem hopelessly sophisticated by second-grade standards.

But while all the cute-kid caprice sometimes gets cloying, and the "religious oppression bad, imagination and friendship good" messages are simplistic, "Rambow" is still genuine, wholehearted fun. The kid-heavy cast tends to substitute enthusiasm for subtlety, but the way they throw their hearts into their games just makes it easier to get drawn in. Where the large scale and cluttered stage of "Hitchhiker's Guide" was chilly and distancing, "Rambow" keeps a tight and tiny focus and barrels forward with infectious glee and authentic sentiment, from Will's love of fantasy to Lee's love of his unworthy older brother to their school's love of Didier to Didier's hilariously outsized love of himself.

And it's hard to resist the hall-of-mirrors cleverness of a film about how much fun it is to make and watch films. On its face and within its story, "Rambow" is about the redemptive properties of creativity, and how only a camera and a little craft separate the adult art of filmmaking from the childish art of pretending. In "Son Of Rambow," the veil between those two arts is admirably, entertainingly thin.